Been a lurker, first time poster.
i've read through tons of threads regarding service, pda phones, unlocked, locked, etc. I still have no clear view of what to do. I will try to make this concise, but would love opinions as to what to get as well as what plan.
Details are:

-currently Cingular blue, contract ends in November, on great family plan 3 phones, no PDA phones currently
-I exclusively have apple/mac computers
-I currently use mac mail application
-I have a .mac account and a hosted domain website account (with email)
-I travel overseas once or twice a year, mostly Australia, love the idea of prepaid sim
-I travel a lot in the states

What I need:
-I need a good email phone that receives email automatically and frequently
-I would like it if the email messages on computer and phone mirrored one another.
-I need to receive email from my domain and from .mac account (I guess through pop3 or imap)
-address book sync
-calendar sync
-a reasonable data plan (I don't want to pay $40+ a month for data only)

What I don't need:
-I don't need all the extra apps of a typical treo, even though they might be nice
-I don't need fast browser access, although checking flights and weather is good
-I don't need the latest and greatest

I see the blackberry users and am quite envious of how it handles email so quickly, but then I see how treo's can sync data quite easily with Macs.

I also don't want to move up to Cingular orange, as there are all the startup transition fees $20 per phone, my normal rate will also go up at least $10 a month (without even adding data). I will have to sign another 2 year agreement, etc...

I need to stay with Macs...but after reading tons of threads of both blackberry and treo's, it looks like there is no really fantastic solution being a at&t customer, mac user, email needing, not wanting to pay high data rates, kind of person....

Also is there any downside to the slower cingular blue sim cards (from what I understand).

Any suggestions:
I'm open to adding a simple data account with another carrier as well, so when november rolls around, I can do go to the right carrier, whether it's cingular orange or another one.

I've looked at both locked and unlocked
600s, 650s, and 7290s